An ATM is a familiar feature of most banking facilities, introduced for allowing bank depositors access to their accounts after banking hours. Access to a particular account is permitted by such a machine in response to a magnetic code encoded on a magnetic stripe on the card. The card is introduced, at a slot in the face of the ATM, to a tray along which the card is moved past read and write heads. The read and write heads decode and encode the magnetic stripe respectively.
Although ATM's are extremely important machines and their use is increasing, they are hard to maintain in operating condition. The main reason for the maintenance problem is the introduction of unauthorized items into the machine at the card input slot. These items, such a sticks and knives, get jammed in the card-receiving mechanism and could even cause damage to the card writing and reading apparatus.
The problem to which the present invention is directed is to provide an ATM which will accept only legitimate cards thus eliminating the possibility of access to the ATM by items other then authorized cards.